FRIDAY, July 13 (HealthDay News) -- Movies often stereotype people with schizophrenia as being violent and unpredictable, says a researcher who claims Hollywood dispenses misinformation about symptoms, causes and treatment of this mental illness.

For the study, published in the July issue of Psychiatric Services, Patricia Owen of the psychology department at St. Mary's University in San Antonio, Texas, reviewed 41 English-language films released between 1990 and 2010 that featured at least one main character with schizophrenia.

Owen found that 83 percent of those characters were portrayed as dangerous or violent to others or themselves. Almost one-third engaged in homicidal behavior, and one-quarter committed suicide, the researcher said.

According to the U.S. National Institute of Mental Health, the risk of violence is small among people with schizophrenia. But suicide risk is higher than average. About 10 percent, mostly young men, do kill themselves, the agency notes.

Delusions, auditory and visual hallucinations, and disorganized speech or thought were displayed by most of the characters, the study author pointed out in a news release from the American Psychiatric Association.

But much more common symptoms of schizophrenia -- such as flat affect, lack of speech and lack of motivation -- were seen much less frequently.

Although schizophrenia incidence is nearly equal among women and men, almost 80 percent of the characters with schizophrenia were male, the study found.

The review noted, however, the movies did get some characterizations of schizophrenia right. Specifically, about half of the characters had low socioeconomic status, which is consistent with data on the illness. Moreover, about half of the movies depicted or alluded to the use of medication to treat the mental illness. Psychotherapy and group therapy were not portrayed often.

Owen suggested that more research is needed to understand how films influence public perceptions about schizophrenia, and to determine how to increase empathy and understanding.

Films featuring a character with schizophrenia include A Beautiful Mind and Donnie Darko.